A comparison of four methods for bubble size and void fraction measurements
A comparison of four methods for bubble size and void fraction measurements
复制标题
DOI：
10.1109/48.701193
复制
发表时间：
1998-07-01
影响因子：
4.1
通讯作者：
Farmer, DM
中科院分区：
文献类型：
--
作者：
Vagle, S;Farmer, DM
我们比较了四种不同的气泡传感技术的性能在一系列的环境中，从冲浪区到开阔的海洋：遥感方法，使用高频后向散射，两个原位方法，使用声学谐振器和脉冲传播传感器，和一个散装的方法，使用电导率。技术之间的比较表明，在适当的操作气泡密度范围内的一般一致性，虽然气泡云的空间变异性引入了很大的差异。每种技术都有其优势和局限性。我们的声学谐振器适用于空气分数大于约10（-9）的气泡浓度，脉冲传播声纳适用于空气分数为10（-6）的气泡浓度;两者的上限都受到衰减和折叠散射近似的有效性的限制。两种传感器都可以实现为包含具有高分辨率的宽频率范围，对应于类似于1200 μ m的10 μ m的共振气泡半径。远高于类似于5x 10（-4）的空气分数，使用电导率的体积测量提供了空气分数的测量。在现场声学技术和电导率测量之间，工作空气分数范围存在足够的重叠，以允许比较并证明测量的一致性。单频和多频反向散射声纳可用于低空气分数（
We compare the performance of four different bubble-sensing techniques in a range of environments from the surf zone to the open ocean: a remote sensing method using high-frequency backscatter, two in situ methods using an acoustical resonator and a pulse propagation sensor, and a bulk method using electrical conductivity. Comparisons between the techniques show general consistency within the appropriate operational bubble density ranges, although spatial variability in bubble clouds introduces substantial variance. Each technique has its strengths and limitations. Our acoustical resonator is suitable for bubble concentrations with air fractions greater than approximately 10(-9) and the pulse propagation sonar for air fractions from 10(-6); the upper limit for both is constrained by attenuation and the validity of the Foldy scattering approximation. Both sensors can be implemented to encompass a wide frequency range with high resolution, corresponding to resonant bubble radii of 10 similar to 1200 mu m. Far air fractions higher than similar to 5x10(-4), bulk measurement using electrical conductivity provides a measure of air fraction. Sufficient overlap in operational air-fraction range exists between in situ acoustical techniques and conductivity measurement to permit comparison and demonstrate consistency in the measurement, Single- and multifrequency backscatter sonars may be used for low air fractions (